1. Field of the Invention
The present invention relates to an optical device processing method.
2. Description of the Related Art
A plurality of optical devices such as LEDs (Light Emitting Diodes) and LDs (Laser Diodes) are formed by growing an epitaxial layer (crystal layer) on a substrate for crystal growth and forming a plurality of crossing division lines for partitioning the epitaxial layer into a plurality of regions where the plural optical devices are respectively formed. The crystal growth substrate having the plural optical devices is divided along the division lines to obtain a plurality of individual optical device chips.
In an optical device chip having a light emitting layer of InGaN for emitting green or blue light, sapphire is generally used for the crystal growth substrate. An n-type GaN semiconductor layer, an InGaN light emitting layer, and a p-type GaN semiconductor layer are sequentially formed on the sapphire substrate by epitaxial growth. Further, electrodes for external connection are respectively formed on the n-type GaN semiconductor layer and the p-type GaN semiconductor layer, thus forming an optical device.
In an optical device such as LEDs, higher luminance is demanded, and it is therefore desired to improve light extraction efficiency. In recent years, an optical device mounted by flip-chip bonding as disclosed in Japanese Patent Laid-open No. Hei 4-10670 has already been widely spread in the market. In such a flip-chip mounted optical device, light emitted from the light emitting layer toward the outside is not blocked by the electrodes, so that the light extraction efficiency is improved over an optical device mounted by conventional wire bonding.